This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A111397 #11 Mar 23 2024 17:32:30
%S A111397 1,0,2,0,1,0,2,0,1,0,2,0,1,0,1,2,0,1,0,2,0,1,2,0,2,0,1,0,2,0,1,0,1,2,
%T A111397 0,1,0,1,2,0,1,0,2,0,1,2,0,2,0,1,0,2,0,1,2,0,2,0,1,0,1,2,0,1,0,1,2,0,
%U A111397 1,2,0,2,0,1,0,2,0,1,0,2,0,1,0,1,2,0,1,2,0,1,2,0,1,2,0,2,0,1,0,1,2,0,1,0,2
%N A111397 Composite numbers (modulo 3).
%C A111397 If the terms of this sequence are interpreted as the base-3 expansion of a real number, its value is 0.4124999703972179190135867434954940067125524729635148630103267345... and its continued fraction expansion is 0, 2, 2, 2, 1, 4, 5278, 131, 4, 2, 2, 2, 2, 1, 24, 12, 1, 1, 7, 552, 1, 2, 1, ... with increasing partial quotients 2, 4, 5278, 66292, 274715, 420778, 625399, ...
%F A111397 a(n) == A002808(n) (mod 3).
%t A111397 Composite[n_] := FixedPoint[n + PrimePi[ # ] + 1 &, n]; Table[ Mod[Composite[n], 3], {n, 105}]
%Y A111397 Cf. A002808, A073867.
%K A111397 nonn
%O A111397 1,3
%A A111397 _Robert G. Wilson v_, Nov 11 2005